Choice quotations on Dostoevsky and Gide, from Maritain's Art and Poetry:

Dostoievsky* never sent his younger brother to seek freedom in sin more daringly than he had done himself. He loved this brother too much, he had made his own voyage with too much sagacity, he knew too well what sin is.

Later,

“Dostoievsky is not properly speaking a thinker, he is a novelist.” Andre Gide explains to us very well that clumsy as he is in expressing his thoughts on his own account and on the abstract plane, Dostoievsky mingles them with the flesh and blood of his characters and makes them live in them; they are not the ideas of a philosopher , contemplative ideas, they are the ideas of an artist, factive ideas. Nothing could be more exact—provided it is added that this novelist is a theologian-novelist, a prophet-novelist. But then, let us beware, in trying to disentangle his thoughts, of misjudging the admirable complexity of the creative synthesis, of attributing to the artist in too brutal a manner, as issuing directly from him, what is not his except through and in the matter that he animates, what does not manifest his thought save by the rays a thousand times refracted, and by the total distribution of the light, and by the portions of shadow as much as by the light.

And finally,

Every novel is a mirror borne along before the futuribilia** and before the laws of divine government, and the novelist who does not believe in moral values destroys in himself the very matter of his art. In behalf of that one of his characters who most resembles his own confession, Stravoguin of The Demons, Dostoievsky contrives no alibi, he leads him to his miserable suicide with a severity, a clairvoyance, a logic without pity. He loves him however, for it is himself, or at least the dark face of himself. But it is exactly here that best appears, in my sense, the transcendence of his genius as a novelist. His work is similar to the living universe, there is in it a sort of metaphysical pathos because the beings who move about in it are, to a certain degree, in the same relation to the thought that creates them, as men are to God. He loves his characters, more tenderly perhaps than does any other artist, he puts himself into them more than does any other; at the same time, he scrutinizes them and judges them inflexibly.

* In context Maritain clearly means In contrast to Gide...

** Maritain explains: "The theologians call futuribilia the events which would have come to pass according to divine foreknowledge, if something which did not take place had taken place at a given moment."